CYP3A4 genetic variant and disease-free survival among white and black men after radical prostatectomy

Prostate cancer is an androgen sensitive disease. Cytochrome P450 3A4 (CYP3A4) oxidatively deactivates testosterone by converting it to biologically less active metabolites. Previous studies suggest that a germline genetic variant in the 5' regulatory region of the gene may interfere with deactivation and increase the risk of clinically advanced prostate cancer. We investigated the impact of this polymorphism on the risk of recurrence after prostatectomy.

We assembled clinical data and analyzed specimens from a large series of patients who underwent prostatectomy who were carefully staged at a single institution and had 5 to 10 years of prospective clinical followup. The series included 428 white men and 309 black men.

Stage, Gleason score or preoperative prostate specific antigen strongly predicted progression-free survival (PFS) but were not associated with CYP3A4 genotypes. There was a strong association between race and genotype (p = 0.00002) in that 8% of white men and 83% of black men had 1 or more copies of the G allele. When both races were included genotype was associated with PFS (hazard ratio [HR] 1.27, CI 1.08-1.27, p = 0.005). In race specific analyses increasing copies of the G allele were associated with poorer PFS among white men (HR 1.98, CI 1.06-3.70, p = 0.03) but had little impact on PFS among black men (HR 1.004, CI 0.77-1.32, p = 0.97).

The CYP3A4 genotype studied was not associated with pathological features of prostate cancer for men of either race. Unstratified analyses of men of both races and stratified analyses of white men demonstrated poorer PFS after prostatectomy for those with the G allele, but the G allele did not predict PFS among black men.